Should structural interventions be evaluated using RCTs? The case of HIV prevention

Community mobilisation approaches to preventing adolescent multiple risk behaviour: a realist review

BACKGROUND

Adolescent multiple risk behaviour (MRB) is a global health issue. Most interventions have focused on the proximal causes of adolescent MRB such as peer or family influence, with systematic reviews reporting mixed evidence of effectiveness. There is increasing recognition that community mobilisation approaches could be beneficial for adolescent health. There are gaps in the current literature, theory and implementation that would benefit from a realist approach. We use a theory-driven evidence synthesis to assess how and why community mobilisation interventions work/do not work to prevent adolescent MRB and in what contexts.

METHODS

This realist review used a six-stage iterative process, guided by the RAMESES framework. We systematically searched PubMed, MEDLINE, PsycINFO, Web of Science, CINAHL and Sociological Abstracts, from their inception to 2021. Studies were screened for relevance to the programme theory, assessed for rigour and included based on a priori criteria. Two independent reviewers selected, screened and extracted data from included studies. A realist logic of analysis was used to develop context-mechanism-outcome configurations that contributed to our programme theory.

FINDINGS

We reviewed 35 documents describing 22 separate community mobilisation intervention studies. Most studies (n = 17) had a quality assessment score of three or four (out of four). We analysed the studies in relation to three middle range theories. To uphold our theory that these interventions work by creating a social environment where adolescents are less likely to engage in MRB, interventions should: (1) embed a framework of guiding principles throughout the community, (2) establish community readiness with population data and (3) ensure a diverse coalition with the support of intervention champions. Mechanisms such as empowerment through coalition ownership over the delivery of the intervention, cohesion across the community and motivation to work collaboratively to improve adolescent health are triggered to achieve social environment shifts. However, certain contexts (e.g. limited funding) restrict intervention success as these mechanisms are not fired.

CONCLUSIONS

For community mobilisation interventions to reduce adolescent MRB, the coalitions within them must seek to alter the social environment in which these behaviours occur. Mechanisms including empowerment, cohesion and motivation lead to this shift, but only under certain contexts.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020205342.

The impact of income-support interventions on life course risk factors and health outcomes during childhood: a systematic review in high income countries

BACKGROUND

In high income countries one in five children still lives in poverty, which is known to adversely shape the life course health trajectory of these children. However, much less is understood on whether social and fiscal policies have the capacity to reverse this damage, which intervention is likely to be most effective and when these interventions should be delivered to maximise their impact. This systematic review attempts to address these questions by looking at the impact of income-support interventions, delivered during the first 1,000 days of life, on cardiovascular, metabolic, respiratory and mental health outcomes.

METHODS

The review was restricted to experimental or quasi experimental studies conducted in high income countries. Studies were retrieved from multidisciplinary databases as well as health, economic, social sciences-specific literature browsers. All papers retrieved through the search strategy were double screened at title, abstract and full text stage. Relevant data of the selected studies were extracted and collected in tables, then summarised via narrative synthesis approach. Robustness of findings was assessed by tabulating impact by health outcome, type of intervention and study design.

RESULTS

Overall, 16 relevant papers were identified, including 15 quasi-experimental studies and one randomized control trial (RCT). Income-support interventions included were unconditional/conditional cash transfers, income tax credit and minimum wage salary policies. Most studies were conducted in United States and Canada. Overall, the evidence suggested limited effect on mental health indicators but a positive, albeit small, effect of most policies on birth weight outcomes. Despite this, according to few studies that tried to extrapolate the results into public health terms, the potential number of negative outcomes averted might be consistent.

CONCLUSIONS

Income-support interventions can positively affect some of the health outcomes of interest in this review, including birth weight and mental health. Given the large number of people targeted by these programs, one could infer that - despite small - the observed effect may be still relevant at population level. Nonetheless, the limited generalisability of the evidence gathered hampers firm conclusions. For the future, the breadth and scope of this literature need to be broadened to fully exploit the potential of these interventions and understand how their public health impact can be maximised.

CauRuler: Causal irredundant association rule miner for complex patient trajectory modelling

BACKGROUND AND OBJECTIVES

Discovering causal associations between variables is one of the main goals of clinical trials, with the ultimate aim of identifying the causes of specific health status. Prior knowledge of causal paths could help ensure patients do not develop the resultant conditions. In recent years, thanks to the enormous amount of health data stored with the support of digital tools, attempts have been made to employ Machine Learning to infer causality. Those methodologies suffer from some deficiencies in controlling cofounders when analysing causality, as well as providing causal rules general enough to be useful in healthcare practice. Conversely, this work presents and evaluates CauRuler, a new approach to deal with causality from association rules. The proposed approach uses a pruning strategy to reduce the association rule set, which does not compromise the causality learning capability of the algorithm. This behaviour makes the algorithm suitable for exploiting large health databases with thousands of patients and medical instances. CauRuler can control a larger number of confounders than other proposals, bringing robustness to causal analysis and avoiding the identification of spurious associations. Additionally, the method generalizes causality using anti-monotone properties to obtain complex and general causal paths. The method can target correct causal associations in complex medical databases with retrospective data.

METHOD

CauRuler extends association rule mining with an irredundancy property so that the set of rules learnt is reduced in size and generalized. General association rules, conformed by fewer items, enable controlling more confounding variables to verify, with more statistical evidence on available data, if they represent causal paths in patient disease trajectories.

RESULTS

CauRuler has been tested on a complex real medical database (3,5 M visits to the primary care services between 2019 and 2020, and controlling over 15.000 different variables including diagnoses and demographic and other clinical patient data). The reduction of the rule set achieved by the pruning strategy goes from 7.732 to 2.240 rules, from which 46 have been found to have causality relationships in the patient trajectories, and generalized to 14 rules tested as true causal relationships thanks to the confounding analysis. These rules have been validated by clinicians with the support of a graphical map. The obtained causal paths control in average of 906 confounder variables, retrieving robust results.

CONCLUSIONS

Causal relationships enable predicting causal paths between health conditions according to patient trajectories. Knowing these causal paths is crucial for understanding and preventing the appearance or worsening of diseases in patients. CauRuler, with high demanding thresholds, has proven its efficiency and effectiveness in targeting previously known causal associations between diagnoses, reaching consensus in the medical community. Softening these thresholds should help target interesting general causal paths.

Community mobilisation approaches to preventing and reducing adolescent multiple risk behaviour: a realist review protocol

BACKGROUND

Adolescent multiple risk behaviour (MRB) continues to be a global health issue. Most interventions have focused on the proximal causes of adolescent MRB such as peer or family influence, rather than targeting the wider environmental or structural context. There is increasing recognition that community mobilisation approaches could be beneficial for adolescent health. Despite this, there are gaps in the current literature, theory and implementation that would benefit from a realist approach due to the suitability of this methodology to analysing complex interventions. The objective of this study is to understand 'how, why, for whom and in what circumstances and time periods' do community mobilisation interventions work to prevent and/or reduce adolescent multiple risk behaviour.

METHODS

This is a protocol for a realist review. The review will use a six-stage iterative process, guided by the RAMESES framework. We will systematically search PubMed, MEDLINE, PsycINFO, Web of Science, CINAHL and Sociological Abstracts, from their inception to 2021. Studies will be screened for relevance to the programme theory and included based on a priori eligibility criteria including (1) reporting a community mobilisation intervention (2) targeting two health risk behaviors (3) for adolescent populations. Two independent reviewers will select, screen and extract data related to the program theory from all relevant sources. A realist logic of analysis will be used to identify all context-mechanism-outcome configurations that contribute to our programme theory. The findings will be synthesised to produce a refined programme theory model.

DISCUSSION

The goal of this realist review is to identify and refine a programme theory for community mobilisation approaches to the prevention and/or reduction of adolescent multiple risk behaviour. Our aim is that the findings surrounding the programme theory refinement can be used to develop and implement adolescent multiple risk behaviour interventions and maintain collaboration between local policy makers, researchers and community members.

SYSTEMATIC REVIEW REGISTRATION

This realist review is registered on the PROSPERO database (registration number: CRD42020205342).

An Islamic Microfinance Approach to Scaling up the Economic Life of Vulnerable People with HIV/AIDS in the Muslim Society

People with HIV/AIDS (PLWHA) commonly pose problems to their family as well as to society because of their vulnerable health and economic conditions. Contrarily, PLWHA encounter social discrimination and adverse realities while finding it difficult to continue in their jobs. These complex phenomena interact to push them into a low economic status. A microfinance program can hopefully assist poor patients to cope with the negative economic consequences of this disease. But the conventional market-oriented microfinance institutions show reluctance to serve this group of people due to the possibilities of having credit risk. In this paper, we propose an alternative microfinancing technique that can provide a better economic life of the PLWHA while absorbing the credit risks. A comprehensive model is designed using specific Islamic financial instruments in conjugation with household economic portfolio theory. Critical realism method was adopted to construct this model. We concluded that the application of Islamic microfinance can enhance income of HIV patients while reducing the productivity-loss. This model can be useful to the microfinance practitioners and policymakers for addressing a different market segment, diversifying products, and formulating policy.

A cluster randomized trial of community mobilization to reduce methamphetamine use and HIV risk among youth in Thailand: Design, implementation and results

BACKGROUND

Use of methamphetamines (MA) and other stimulants have consistently been associated with HIV/STI risk globally. We evaluated a community mobilization intervention (Connect to Protect, C2P^®) to prevent MA use among youth and reduce HIV risk behaviors through community structural changes.

DESIGN

A community-randomized trial in northern Thailand with matched districts randomized to C2P intervention or a standard voluntary counseling and testing (VCT) control. Intervention districts formed stakeholders' coalitions to plan tailored local prevention programs. Two independent random household samples of youth aged 14-24 were surveyed in 2009 and 2012. Lifetime and recent MA use was modeled with multilevel logistic regression.

RESULTS

Intervention initiatives included family-strengthening programs, school-based programs and opening a community drug treatment center. Control communities applied the government-led "war on drugs" approach in addition to youth and family programs. Baseline (N = 1077) and follow-up (N = 1225) samples included 47.5% females and 21.7% aged ≤16. Lifetime MA use in intervention districts reduced from 13.4% to 11.7% compared to reduction from 16.2% to 10.4% in the control districts (non-significant). In models, lifetime MA use was associated with: time (aOR = 0.6, 95%CI: 0.38-0.83), females (aOR = 0.2, 95%CI: 0.15-0.29), increasing age (aOR = 2.4, 95%CI: 1.40-4.20, ages 16-19; aOR = 3.5, 95%CI: 2.00-6.12, ages ≥20), and not being full-time students (aOR = 5.3, 95%CI: 3.77-7.37). Recent MA use showed similar results. Additionally, lifetime MA use was significantly associated with alcohol use, risky sexual behaviors and elevated depressive symptoms.

CONCLUSIONS

Delay in developing and implementing specific prevention programs in the intervention districts slowed diffusion of the effect into the communities. Secular trends with contentious civil unrest and active drug-enforcement efforts in the control communities also contributed to the null intervention effect. Longer time and intensified efforts stressing a public health approach are needed to demonstrate the effectiveness of community mobilization in reducing substance use and HIV risk in this rural Thai community.

Evaluations of Structural Interventions for HIV Prevention: A Review of Approaches and Methods

Structural interventions alter the social, economic, legal, political, and built environments that underlie processes affecting population health. We conducted a systematic review of evaluations of structural interventions for HIV prevention in low- and middle-income countries (LMICs) to better understand methodological and other challenges and identify effective evaluation strategies. We included 27 peer-reviewed articles on interventions related to economic empowerment, education, and substance abuse in LMICs. Twenty-one evaluations included clearly articulated theories of change (TOCs); 14 of these assessed the TOC by measuring intermediary variables in the causal pathway between the intervention and HIV outcomes. Although structural interventions address complex interactions, no evaluation included methods designed to evaluate complex systems. To strengthen evaluations of structural interventions, we recommend clearly articulating a TOC and measuring intermediate variables between the predictor and outcome. We additionally recommend adapting study designs and analytic methods outside traditional epidemiology to better capture complex results, influences external to the intervention, and unintended consequences.

Structural and Community Change Outcomes of the Connect-to-Protect Coalitions: Trials and Triumphs Securing Adolescent Access to HIV Prevention, Testing, and Medical Care

Connect to Protect (C2P), a 10-year community mobilization effort, pursued the dual aims of creating communities competent to address youth's HIV-related risks and removing structural barriers to youth health. We used Community Coalition Action Theory (CCAT) to examine the perceived contributions and accomplishments of 14 C2P coalitions. We interviewed 318 key informants, including youth and community leaders, to identify the features of coalitions' context and operation that facilitated and undermined their ability to achieve structural change and build communities' capability to manage their local adolescent HIV epidemic effectively. We coded the interviews using an a priori coding scheme informed by CCAT and scholarship on AIDS-competent communities. We found community mobilization efforts like C2P can contribute to addressing the structural factors that promote HIV-risk among youth and to community development. We describe how coalition leadership, collaborative synergy, capacity building, and local community context influence coalitions' ability to successfully implement HIV-related structural change, demonstrating empirical support for many of CCAT's propositions. We discuss implications for how community mobilization efforts might succeed in laying the foundation for an AIDS-competent community.

Evaluating Structural Change Approaches to Health Promotion: An Exploratory Scoping Review of a Decade of U.S. Progress

Structural change approaches—also known as policy and environmental changes—are becoming increasingly common in health promotion, yet our understanding of how to evaluate them is still limited. An exploratory scoping review of the literature was conducted to understand approaches and methods used to evaluate structural change interventions in health promotion and public health literature. Two analysts—along with health sciences librarian consultation—searched PubMed, Web of Science, and EMBASE for peer-reviewed U.S.-based, English language studies published between 2005 and 2016. Data were extracted on the use of evaluation frameworks, study designs, duration of evaluations, measurement levels, and measurement types. Forty-five articles were included for the review. Notably, the majority (73%) of studies did not report application of a specific evaluation framework. Studies used a wide range of designs, including process evaluations, quasi- or nonexperimental designs, and purely descriptive approaches. In addition, 15.6% of studies only measured outcomes at the individual level. Last, 60% of studies combined more than one measurement type (e.g., site observation + focus groups) to evaluate interventions. Future directions for evaluating structural change approaches to health promotion include more widespread use and reporting of evaluation frameworks, developing validated tools that measure structural change, and shifting the focus to health-directed approaches, including an expanded consideration for evaluation designs that address health inequities.

Creating Youth-Supportive Communities: Outcomes from the Connect-to-Protect® (C2P) Structural Change Approach to Youth HIV Prevention

Reducing HIV incidence among adolescents represents an urgent global priority. Structural change approaches to HIV prevention may reduce youth risk by addressing the economic, social, cultural, and political factors that elevate it. We assessed whether achievement of structural changes made by eight Connect-to-Protect (C2P) coalitions were associated with improvements in youth's views of their community over the first 4 years of coalitions' mobilization. We recruited annual cross-sectional samples of targeted youth from each C2P community. We sampled youth in neighborhood venues. We interviewed a total of 2461 youth over 4 years. Males (66 %) and youth of color comprised the majority (52 % Hispanic/Latinos; 41 % African Americans) of those interviewed. By year 4, youth reported greater satisfaction with their community as a youth-supportive setting. They reported their needs were better met by available community resources compared with year 1. However, these findings were moderated by risk population such that those from communities where C2P focused on young men who have sex with men (YMSM) reported no changes over time whereas those from communities focused on other at-risk youth reported significant improvements over time in satisfaction and resource needs being met. Internalized HIV stigma increased over time among those from communities serving other at-risk youth and was unchanged among those from YMSM communities. The very different results we observe over time between communities focused on YMSM versus other at-risk youth may suggest it is unreasonable to assume identical chains of structural causality across youth populations who have such different historical relationships to HIV and who encounter very different kinds of entrenched discrimination within their communities.

Evaluation of the effect of human immunodeficiency virus-related structural interventions: the connect to protect project

IMPORTANCE

With the emphasis on structural-level interventions that target social determinants of human immunodeficiency virus (HIV) transmission to curb the HIV epidemic, there is a need to develop evaluation models that can detect changes in individual factors associated with HIV-related structural changes.

OBJECTIVE

To describe whether structural changes developed and achieved by community coalitions are associated with an effect on individual factors associated with the risk of contracting HIV.

DESIGN, SETTING, AND PARTICIPANTS

In this serial cross-sectional survey design, data were collected from 8 cities during 4 rounds of annual surveys from March 13, 2007, through July 29, 2010. Study recruitment took place at venues where the population of focus was known to congregate, such as clubs, bars, community centers, and low-income housing. The convenience sample of at-risk youth (persons aged 12-24 years) included 5337 individuals approached about the survey and 3142 (58.9%) who were screened for eligibility. Of the 2607 eligible participants, 2559 (98.2%) ultimately agreed to participate.

INTERVENTIONS

Achievement of locally identified structural changes that targeted public and private entities (eg, federal agencies, homeless shelters, and school systems) with the goal of fostering changes in policy and practice to ultimately facilitate positive behavioral changes aimed at preventing HIV.

MAIN OUTCOMES AND MEASURES

Number of sexual partners, partner characteristics, condom use, and history of sexually transmitted infections and HIV testing.

RESULTS

Exposure to structural changes was not statistically significantly associated with any of the outcome measures, although some results were in the direction of a positive structural change effect (eg, a 10-unit increase in a structural change score had an odds ratio of 0.88 [95% CI, 0.76-1.03; P = .11] for having an older sexual partner and an odds ratio of 0.91 [95% CI, 0.60-1.39; P = .39] for using a condom half the time or less with a casual partner).

CONCLUSIONS AND RELEVANCE

This study evaluated a broad representation of at-risk individuals and assessed the effect of numerous structural changes related to various HIV risk factors. No structural changes as measured in this study were associated with a statistically significant reduction in risk behaviors. These null findings underscore the need for a long-term approach in evaluating structural interventions and the development of more nuanced methods of quantifying and comparing structural-change initiatives and determining the appropriate strategies for evaluating effect.

The impact of community mobilisation on HIV prevention in middle and low income countries: a systematic review and critique

While community mobilisation (CM) is increasingly advocated for HIV prevention, its impact on measurable outcomes has not been established. We performed a systematic review of the impact of CM within HIV prevention interventions (N = 20), on biomedical, behavioural and social outcomes. Among most at risk groups (particularly sex workers), the evidence is somewhat consistent, indicating a tendency for positive impact, with stronger results for behavioural and social outcomes than for biomedical ones. Among youth and general communities, the evidence remains inconclusive. Success appears to be enhanced by engaging groups with a strong collective identity and by simultaneously addressing the socio-political context. We suggest that the inconclusiveness of the findings reflects problems with the evidence, rather than indicating that CM is ineffective. We discuss weaknesses in the operationalization of CM, neglect of social context, and incompatibility between context-specific CM processes and the aspiration of review methodologies to provide simple, context-transcending answers.

Population-based study of food insecurity and HIV transmission risk behaviors and symptoms of sexually transmitted infections among linked couples in Nepal

Food insecurity has recently emerged as an important risk factor for HIV acquisition among women worldwide. No previous studies have used linked data that would permit investigation of the extent to which food insecurity may have differential associations with HIV transmission risk behaviors or symptoms of sexually transmitted infections (STIs) among men and women in the same households. We used nationally representative data on linked couples from the Nepal 2011 Demographic and Health Survey. The primary explanatory variable of interest was food insecurity, measured with a modified version of the Household Food Insecurity Access Scale. In multivariable logistic regression models, women in food insecure households were less likely to report recent condom use and more likely to report symptoms consistent with STIs. These patterns were absent among men. Interventions targeting food insecurity may have beneficial implications for both HIV prevention and gender equity in Nepal.

The Benefits of Youth Engagement in HIV-Preventive Structural Change Interventions

Youth are infrequently included in planning the health promotion projects designed to benefit them as many of the factors infringing upon youth's health and well-being also limit their engagement in community-based public health promotion projects. This article explores youth engagement in 13 coalitions implementing structural changes meant to reduce HIV transmission among adolescents. There was wide variation of youth membership and involvement across coalitions. Using analytic induction, the authors show that youth engagement was associated with the successful completion of structural change efforts. The authors also describe how youth engagement indirectly facilitated coalitions' success. The authors suggest that youth engagement in planning and conducting structural interventions is itself a valuable structural change.

Methods and protocol of a mixed method quasi-experiment to evaluate the effects of a structural economic and food security intervention on HIV vulnerability in rural Malawi: The SAGE4Health Study

Background

Poverty and lack of a predictable, stable source of food are two fundamental determinants of ill health, including HIV/AIDS. Conversely, episodes of poor health and death from HIV can disrupt the ability to maintain economic stability in affected households, especially those that rely on subsistence farming. However, little empirical research has examined if, and how, improvements in people’s economic status and food security translate into changes in HIV vulnerability.

Methods

In this paper, we describe in detail the methods and protocol of an academic-NGO collaboration on a quasi-experimental, longitudinal study of the mechanisms and magnitude of the impact of a multilevel economic and food security program (Support to Able-Bodied Vulnerable Groups to Achieve Food Security; SAFE), as implemented by CARE. Primary outcomes include HIV vulnerability (i.e., HIV risk behaviors, HIV infection), economic status (i.e., income, household assets) and food security (including anthropometric measures). We recruited participants from two types of areas of rural central Malawi: traditional authorities (TA) selected by CARE to receive the SAFE program (intervention group) and TAs receiving other unrelated CARE programming (controls). In the intervention TAs, we recruited 598 program participants (398 women, 200 men) and interviewed them at baseline and 18- and 36-month follow-ups; we interviewed 301 control households. In addition, we conducted random surveys (n = 1002) in the intervention and control areas with a 36-month assessment interval, prior to and after implementation of SAFE. Thus, we are examining intervention outcomes both in direct SAFE program participants and their larger communities. We are using multilevel modeling to examine mediators and moderators of the effects of SAFE on HIV outcomes at the individual and community levels and determine the ways in which changes in HIV outcomes feed back into economic outcomes and food security at later interviews. Finally, we are conducting a qualitative end-of-program evaluation consisting of in-depth interviews with 90 SAFE participants.

Discussion

In addition to examining pathways linking structural factors to HIV vulnerability, this research will yield important information for understanding the impact of a multilevel environmental/structural intervention on HIV, with the potential for other sustainable long-term public health benefits.

Community empowerment and involvement of female sex workers in targeted sexual and reproductive health interventions in Africa: a systematic review

Background

Female sex workers (FSWs) experience high levels of sexual and reproductive health (SRH) morbidity, violence and discrimination. Successful SRH interventions for FSWs in India and elsewhere have long prioritised community mobilisation and structural interventions, yet little is known about similar approaches in African settings. We systematically reviewed community empowerment processes within FSW SRH projects in Africa, and assessed them using a framework developed by Ashodaya, an Indian sex worker organisation.

Methods

In November 2012 we searched Medline and Web of Science for studies of FSW health services in Africa, and consulted experts and websites of international organisations. Titles and abstracts were screened to identify studies describing relevant services, using a broad definition of empowerment. Data were extracted on service-delivery models and degree of FSW involvement, and analysed with reference to a four-stage framework developed by Ashodaya. This conceptualises community empowerment as progressing from (1) initial engagement with the sex worker community, to (2) community involvement in targeted activities, to (3) ownership, and finally, (4) sustainability of action beyond the community.

Results

Of 5413 articles screened, 129 were included, describing 42 projects. Targeted services in FSW ‘hotspots’ were generally isolated and limited in coverage and scope, mostly offering only free condoms and STI treatment. Many services were provided as part of research activities and offered via a clinic with associated community outreach. Empowerment processes were usually limited to peer-education (stage 2 of framework). Community mobilisation as an activity in its own right was rarely documented and while most projects successfully engaged communities, few progressed to involvement, community ownership or sustainability. Only a few interventions had evolved to facilitate collective action through formal democratic structures (stage 3). These reported improved sexual negotiating power and community solidarity, and positive behavioural and clinical outcomes. Sustainability of many projects was weakened by disunity within transient communities, variable commitment of programmers, low human resource capacity and general resource limitations.

Conclusions

Most FSW SRH projects in Africa implemented participatory processes consistent with only the earliest stages of community empowerment, although isolated projects demonstrate proof of concept for successful empowerment interventions in African settings.

Multilevel dynamic systems affecting introduction of HIV/STI prevention innovations among Chinese women in sex work establishments

Social and public health scientists are increasingly interested in applying system dynamics theory to improve understanding and to harness the forces of change within complex, multilevel systems that affect community intervention implementation, effects, and sustainability. Building a system dynamics model based on ethnographic case study has the advantage of using empirically documented contextual factors and processes of change in a real-world and real-time setting that can then be tested in the same and other settings. System dynamics modeling offers great promise for addressing persistent problems like HIV and other sexually transmitted epidemics, particularly in complex rapidly developing countries such as China. We generated a system dynamics model of a multilevel intervention we conducted to promote female condoms for HIV/sexually transmitted infection (STI) prevention among Chinese women in sex work establishments. The model reflects factors and forces affecting the study's intervention, implementation, and effects. To build this conceptual model, we drew on our experiences and findings from this intensive, longitudinal mixed-ethnographic and quantitative four-town comparative case study (2007-2012) of the sex work establishments, the intervention conducted in them, and factors likely to explain variation in process and outcomes in the four towns. Multiple feedback loops in the sex work establishments, women's social networks, and the health organization responsible for implementing HIV/STI interventions in each town and at the town level directly or indirectly influenced the female condom intervention. We present the conceptual system dynamics model and discuss how further testing in this and other settings can inform future community interventions to reduce HIV and STIs.

Explaining the effects of two different strategies for promoting hand hygiene in hospital nurses: a process evaluation alongside a cluster randomised controlled trial

Background

There is only limited understanding of why hand hygiene improvement strategies are successful or fail. It is therefore important to look inside the ‘black box’ of such strategies, to ascertain which components of a strategy work well or less well. This study examined which components of two hand hygiene improvement strategies were associated with increased nurses’ hand hygiene compliance.

Methods

A process evaluation of a cluster randomised controlled trial was conducted in which part of the nursing wards of three hospitals in the Netherlands received a state-of-the-art strategy, including education, reminders, feedback, and optimising materials and facilities; another part received a team and leaders-directed strategy that included all elements of the state-of-the-art strategy, supplemented with activities aimed at the social and enhancing leadership. This process evaluation used four sets of measures: effects on nurses’ hand hygiene compliance, adherence to the improvement strategies, contextual factors, and nurses’ experiences with strategy components. Analyses of variance and multiple regression analyses were used to explore changes in nurses’ hand hygiene compliance and thereby better understand trial effects.

Results

Both strategies were performed with good adherence to protocol. Two contextual factors were associated with changes in hand hygiene compliance: a hospital effect in long term (p < 0.05), and high hand hygiene baseline scores were associated with smaller effects (p < 0.01). In short term, changes in nurses’ hand hygiene compliance were positively correlated with experienced feedback about their hand hygiene performance (p < 0.05). In the long run, several items of the components ‘social influence’ (i.e., addressing each other on undesirable hand hygiene behaviour p < 0.01), and ‘leadership’ (i.e., ward manager holds team members accountable for hand hygiene performance p < 0.01) correlated positively with changes in nurses’ hand hygiene compliance.

Conclusion

This study illustrates the use of a process evaluation to uncover mechanisms underlying change in hand hygiene improvement strategies. Our study results demonstrate the added value of specific aspects of social influence and leadership in hand hygiene improvement strategies, thus offering an interpretation of the trial effects.

Trial registration

The study is registered in ClinicalTrials.gov, dossier number: NCT00548015.

A community mobilisation intervention to prevent violence against women and reduce HIV/AIDS risk in Kampala, Uganda (the SASA! Study): study protocol for a cluster randomised controlled trial

BACKGROUND

Gender based violence, including violence by an intimate partner, is a major global human rights and public health problem, with important connections with HIV risk. Indeed, the elimination of sexual and gender based violence is a core pillar of HIV prevention for UNAIDS. Integrated strategies to address the gender norms, relations and inequities that underlie both violence against women and HIV/AIDS are needed. However there is limited evidence about the potential impact of different intervention models. This protocol describes the SASA!

STUDY

an evaluation of a community mobilisation intervention to prevent violence against women and reduce HIV/AIDS risk in Kampala, Uganda.

METHODS/DESIGN

The SASA! STUDY is a pair-matched cluster randomised controlled trial being conducted in eight communities in Kampala. It is designed to assess the community-level impact of the SASA! intervention on the following six primary outcomes: attitudes towards the acceptability of violence against women and the acceptability of a woman refusing sex (among male and female community members); past year experience of physical intimate partner violence and sexual intimate partner violence (among females); community responses to women experiencing violence (among women reporting past year physical/sexual partner violence); and past year concurrency of sexual partners (among males). 1583 women and men (aged 18-49 years) were surveyed in intervention and control communities prior to intervention implementation in 2007/8. A follow-up cross-sectional survey of community members will take place in 2012. The primary analysis will be an adjusted cluster-level intention to treat analysis, comparing outcomes in intervention and control communities at follow-up. Complementary monitoring and evaluation and qualitative research will be used to explore and describe the process of intervention implementation and the pathways through which change is achieved.

DISCUSSION

This is one of few cluster randomised trials globally to assess the impact of a gender-focused community mobilisation intervention. The multi-disciplinary research approach will enable us to address questions of intervention impact and mechanisms of action, as well as its feasibility, acceptability and transferability to other contexts. The results will be of importance to researchers, policy makers and those working on the front line to prevent violence against women and HIV.

TRIAL REGISTRATION

ClinicalTrials.Gov NCT00790959.

Limits to evidence-based health policymaking: policy hurdles to structural HIV prevention in Tanzania

Despite the well-documented role of highly co-endemic biological cofactors in facilitating HIV transmission and the availability of comparatively inexpensive tools to control them, cofactor-related interventions are only hesitantly included into African HIV prevention strategies. Against this background, this study analyzes political obstacles to policy-uptake of evidence concerning structural HIV prevention. The data used stem from fieldwork conducted in Tanzania between 2007 and 2009. They include 92 in-depth interviews with key AIDS policymakers and observations of 8 national-level policy meetings. Adopting a political economy perspective, the study shows that 1) assuming cost-aversion as a spontaneous reflex of policymakers is empirically wrong and analytically misleading, 2) that political constituencies induce a path dependence of allocative decisions inconducive to structural prevention, 3) that interventions' political attractiveness depends on the nature of their outputs and the expected temporality of political returns, 4) that policy fragmentation entailed by vertical disease control disfavours the consideration of broader causalities, and 5) that cofactor-based measures are hampered by policymakers' perception of structural prevention as being excessively complex and ultimately tantamount to poverty eradication. Confronting the policy players' reading of the Tanzanian situation with recent and classical literature on evidence-based decision-making and the politics of public health, this paper shows that, far from being strictly evidence-driven, HIV prevention policies result from a politically negotiated aggregation of competing, frequently non-optimizing rationalities. A realistic appraisal of policy processes suggests that the failure to consider the invariably political nature of HIV-related policymaking hampers the formulation of effective, politically informed strategies for positive change. Consequently, developing policy practitioners' understanding of how to effectively engage in evidence-influenced political struggles over priorities might be more instrumental in improving HIV prevention strategies than attempts to sidestep these ineradicably antagonistic controversies though technical decision tools meant to optimize health outcomes via the formulation of 'rational consensus'.

Secondary HIV prevention: novel intervention approaches to impact populations most at risk

This paper reviews recent secondary prevention interventions designed to reduce sexual risk behaviors among people living with HIV/AIDS (PLWHA). A summary of findings from previous meta-analyses and narrative reviews of interventions is provided. Next, novel HIV prevention approaches for PLWHA are reviewed. The review reports on the efficacy of interventions delivered in primary care settings or by technology-formats, interventions that also address mental health difficulties, and programs to address particular at-risk populations (eg, men who have sex with men). A critique of recent interventions for people living with HIV/AIDS is provided as well as suggestions for future research.

Potential role of safer injection facilities in reducing HIV and hepatitis C infections and overdose mortality in the United States

BACKGROUND

Safer injection facilities (SIFs) reduce risks associated with injecting drugs, particularly public injection and overdose mortality. They exist in many countries, but do not exist in the United States. We assessed several ethical, operational, and public health considerations for establishing SIFs in the United States.

METHOD

We used the six-factor Kass framework (goals, effectiveness, concerns, minimization of concerns, fair implementation, and balancing of benefits and concerns), summarized needs of persons who inject drugs in the United States, and reviewed global evidence for SIFs.

RESULTS

SIFs offer a hygienic environment to inject drugs, provide sterile injection equipment at time of injection, and allow for safe disposal of used equipment. Injection of pre-obtained drugs, purchased by persons who inject drugs, happens in a facility where trained personnel provide on-site counseling and referral to addiction treatment and health care and intervene in overdose emergency situations. SIFs provide positive health benefits (reducing transmission of HIV and viral hepatitis, bacterial infections, and overdose mortality) without evidence for negative health or social consequences. SIFs serve most-at-risk persons, including those who inject in public or inject frequently, and those who do not use other public health programs. It is critical to address legal, ethical, and local concerns, develop and implement relevant policies and procedures, and assess individual- and community-level needs and benefits of SIFs given local epidemiologic data.

CONCLUSIONS

SIFs have the potential to reduce viral and bacterial infections and overdose mortality among those who engage in high-risk injection behaviors by offering unique public health services that are complementary to other interventions.

A simple new method to triangulate self-reported risk behavior data--the bean method

BACKGROUND

Human immunodeficiency virus (HIV)/sexually transmitted disease (STD)-related interventions rely on self-reported risk behavioral data, which are biased toward social desirability. It is warranted to develop methods for data triangulation.

METHODS

Some questions on HIV/STD-related behaviors that were asked in 5 face-to-face (FTF) surveys were repeated at the end of the surveys, using the newly developed bean method (BM), which requested participants to transfer a bean of a particular color from a large jar to a smaller one, depending on whether the answer was affirmative (yellow, white, green, or red) or not (black); both jars contained 500 mixed-up colored beans. At the end of each day, the number of beans for each color was counted and was compared with the results of the FTF interviews. Participants were ensured that the researchers would not trace their responses.

RESULTS

Among female sex workers who were noninjecting drug users, the BM as compared with the FTF interviews, reported higher prevalence of inconsistent condom use in the last 6 months, unprotected sex with the last client, and STD in the last 6 months. Among men who have sex with men in Hong Kong, the BM as compared to the FTF interviews, reported higher prevalence of unprotected sex with another man and having >3 sex partners in the last 12 months. No statistically significant between-method differences were reported among injecting drug users.

CONCLUSIONS

Results of HIV/STD-related behaviors are dependent on mode of data collection. The simple BM can be used regularly to triangulate self-reported HIV-related behavioral data obtained from FTF interviews.

"They arrested me for loving a schoolgirl": ethnography, HIV, and a feminist assessment of the age of consent law as a gender-based structural intervention in Uganda

In 1990 women's rights activists in Uganda successfully lobbied to amend the Defilement Law, raising the age of sexual consent for adolescent females from fourteen to eighteen years old and increasing the maximum sentence to death by hanging. The amendment can be considered a macro-level intervention designed to address the social and health inequalities affecting young women and girls, particularly their disproportionately high rate of HIV as compared to their male counterparts. While the intention of the law and aggressive campaign was to prosecute "sugar daddies" and "pedophiles," the average age of men charged with defilement was twenty-one years old and many were believe to be "boyfriends" in consensual sexual liaisons with the alleged victims. This article uses court records, case studies, and longitudinal ethnographic data gathered in east-central Uganda to examine the impact of the age of consent law at national and local levels, and specifically what the disjunctures between national intentions and local uses reveal about conflicting views about sexual privilege and rights. I argue that existing class, gender, and age hierarchies have shaped how the Defilement Law has been applied locally, such that despite the stated aim of "protecting" young women, the law reinstates patriarchal privilege (especially against men of lower social class) while simultaneously increasing the regulation of adolescent female sexuality and undermining their autonomy. This paper demonstrates how ethnography and critical gender theory-which emphasizes the intersectionality of gender, age, and class in the (re)production of inequalities-can be used to examine consequences of macro-level interventions in ways that may be undetected in conventional public health evaluation techniques but that are crucial for designing and modifying effective interventions.

The effectiveness of harm reduction in preventing HIV among injecting drug users

There is now compelling evidence that harm reduction approaches to HIV prevention among injecting drug users are effective, safe and cost-effective. The evidence of effectiveness is strongest for needle and syringe programs and opioid substitution treatment. There is no convincing evidence that needle and syringe programs increase injecting drug use. The low prevalence approximately 1%) of HIV among injecting drug users reflects the early adoption and rapid expansion of harm reduction in Australia. Countries that have provided extensive needle and syringe programs and opioid substitution treatment appear to have averted an epidemic, stabilised or substantially reduced the prevalence of HIV among injecting drug users. However, despite decades of vigorous advocacy and scientific evidence, the global coverage of needle and syringe programs and opioid substitution treatment falls well short of the levels required to achieve international HIV control.

A dynamic social systems model for considering structural factors in HIV prevention and detection

We present a model for HIV-related behaviors that emphasizes the dynamic and social nature of the structural factors that influence HIV prevention and detection. Key structural dimensions of the model include resources, science and technology, formal social control, informal social influences and control, social interconnectedness, and settings. These six dimensions can be conceptualized on macro, meso, and micro levels. Given the inherent complexity of structural factors and their interrelatedness, HIV prevention interventions may focus on different levels and dimensions. We employ a systems perspective to describe the interconnected and dynamic processes of change among social systems and their components. The topics of HIV testing and safer injection facilities (SIFs) are analyzed using this structural framework. Finally, we discuss methodological issues in the development and evaluation of structural interventions for HIV prevention and detection.

Toward a comprehensive approach to HIV prevention for people who use drugs

Comprehensive HIV prevention interventions are increasingly recognized as critical in the global effort to reduce HIV transmission among people who use injection drugs. Scientific evidence clearly shows that a variety of biomedical, behavioral, and structural interventions can prevent and reduce injection drug user-driven HIV epidemics, yet social and structural barriers to their implementation remain. This review discusses the scientific evidence on the effectiveness of individual programs for reducing HIV incidence among people who use injection drugs and how, by integrating individual programs as complements within a comprehensive HIV prevention approach, it is possible to achieve, and to sustain, greater results than those of individual programs alone. The article concludes with a discussion of a critical research priority; namely, to improve the implementation of comprehensive HIV prevention interventions in settings of prevalent injection drug use and to overcome the often complex barriers that impede them. Such an effort will require more than research alone, however. It will also require the ongoing commitment of policymakers, public health officials, and the affected communities themselves to use comprehensive HIV treatment and prevention as the most effective strategy to reduce new HIV infections.

Combination prevention: a deeper understanding of effective HIV prevention

Evidence-informed and human rights-based combination prevention combines behavioural, biomedical, and structural interventions to address both the immediate risks and underlying causes of vulnerability to HIV infection, and the pathways that link them. Because these are context-specific, no single prescription or standard package will apply universally. Anchored in 'know your epidemic' estimates of where the next 1000 infections will occur and 'know your response' analyses of resource allocation and programming gaps, combination prevention strategies seek to realign programme priorities for maximum effect to reduce epidemic reproductive rates at local, regional, and national levels. Effective prevention means tailoring programmes to local epidemics and ensuring that components are delivered with the intensity, quality, and scale necessary to achieve intended effects. Structural interventions, addressing the social, economic, cultural, and legal constraints that create HIV risk environments and undermine the agency of individuals to protect themselves and others, are also public goods in their own right. Applying the principles of combination prevention systematically and consistently in HIV programme planning, with due attention to context, can increase HIV programme effectiveness. Better outcome and impact measurement using multiple methods and data triangulation can build the evidence base on synergies between the components of combination prevention at individual, group, and societal levels, facilitating iterative knowledge translation within and among programmes.

Resources and obstacles to developing and implementing a structural intervention to prevent HIV in San Salvador, El Salvador

HIV prevention researchers have increasingly advocated structural interventions that address factors in the social, political and economic context to reduce disparities of HIV/AIDS among disadvantaged populations. This paper draws on data collected in three different types of low-income communities (n=6) in the San Salvador metropolitan area in El Salvador. Nine focus group discussions were conducted between January 2006 and July 2007, 6 with community leaders, and 3 with crack cocaine users, as well as in-depth interviews with 20 crack users and crack dealers. We explore opportunities and barriers to the implementation of a community-level, structural intervention. We first analyze the different forms of leadership, and other community resources including existing HIV prevention activities that could potentially be used to address the related problems of crack use and HIV in the communities, and the structural factors that may act as barriers to capitalizing on communities' strengths in interventions. Each of the communities studied demonstrated different resources that stem from each community's unique history and geographic location. HIV testing and prevention resources varied widely among the communities, with resources concentrated in one Older Central community despite a strong need in all communities. In many communities, fear of gang violence and non-responsiveness by government agencies to communities' needs have discouraged community organizing. In the discussion, we offer concrete suggestions for developing and implementing structural interventions to reduce HIV risks that use communities' different but complementary resources.

Secondary prevention of HIV infection: the current state of prevention for positives

PURPOSE OF REVIEW

To provide a state-of-the-science review of the literature on secondary prevention of HIV infection or 'prevention for positives' (PfP) interventions.

RECENT FINDINGS

Early work on PfP focused on understanding the dynamics of risky behavior among People Living with HIV/AIDS (PLWH) and on designing, implementing, and evaluating a limited number of interventions to promote safer sexual and drug use behavior in this population (i.e., PfP interventions). Previous meta-analyses demonstrated that PfP interventions can effectively promote safer behavior. However, the understanding of risk dynamics among PLWH and the extant number and breadth of effective PfP interventions were scant. Recent work has addressed some of these problems, yielding greater understanding of risk dynamics and providing additional, effective interventions. Still, only a modest number of recent, rigorously evaluated, effective interventions have been identified. New ideas for creating stronger, more integrated, and effective PfP interventions have emerged that will guide future intervention research and practice.

SUMMARY

There remains much to be done to understand why, when, and under what conditions PLWH practice risk. Substantial work also needs to be performed to design, implement, rigorously evaluate, and when effective, to disseminate widely, additional, evidence-based PfP interventions targeting diverse populations. Directing such interventions to populations of PLWH at greatest risk for transmission of HIV has the potential to yield significant impact on the pandemic.

Gender-based violence and HIV: relevance for HIV prevention in hyperendemic countries of southern Africa

Gender-based violence (GBV) is common in southern Africa. Here we use GBV to include sexual and non-sexual physical violence, emotional abuse, and forms of child sexual abuse. A sizeable literature now links GBV and HIV infection.Sexual violence can lead to HIV infection directly, as trauma increases the risk of transmission. More importantly, GBV increases HIV risk indirectly. Victims of childhood sexual abuse are more likely to be HIV positive, and to have high risk behaviours.GBV perpetrators are at risk of HIV infection, as their victims have often been victimised before and have a high risk of infection. Including perpetrators and victims, perhaps one third of the southern African population is involved in the GBV-HIV dynamic.A randomised controlled trial of income enhancement and gender training reduced GBV and HIV risk behaviours, and a trial of a learning programme reported a non-significant reduction in HIV incidence and reduction of male risk behaviours (primary prevention). Interventions among survivors of GBV can reduce their HIV risk (secondary prevention). Various strategies can reduce spread of HIV from infected GBV survivors (tertiary prevention). Dealing with GBV could have an important effect on the HIV epidemic.A policy shift is necessary. HIV prevention policy should recognise the direct and indirect implications of GBV for HIV prevention, the importance of perpetrator dynamics, and that reduction of GBV should be part of HIV prevention programmes. Effective interventions are likely to include a structural component, and a GBV awareness component.

Effect of a brief video intervention on incident infection among patients attending sexually transmitted disease clinics

BACKGROUND

Sexually transmitted disease (STD) prevention remains a public health priority. Simple, practical interventions to reduce STD incidence that can be easily and inexpensively administered in high-volume clinical settings are needed. We evaluated whether a brief video, which contained STD prevention messages targeted to all patients in the waiting room, reduced acquisition of new infections after that clinic visit.

METHODS AND FINDINGS

In a controlled trial among patients attending three publicly funded STD clinics (one in each of three US cities) from December 2003 to August 2005, all patients (n = 38,635) were systematically assigned to either a theory-based 23-min video depicting couples overcoming barriers to safer sexual behaviors, or the standard waiting room environment. Condition assignment alternated every 4 wk and was determined by which condition (intervention or control) was in place in the clinic waiting room during the patient's first visit within the study period. An intent-to-treat analysis was used to compare STD incidence between intervention and control patients. The primary endpoint was time to diagnosis of incident laboratory-confirmed infections (gonorrhea, chlamydia, trichomoniasis, syphilis, and HIV), as identified through review of medical records and county STD surveillance registries. During 14.8 mo (average) of follow-up, 2,042 patients (5.3%) were diagnosed with incident STD (4.9%, intervention condition; 5.7%, control condition). In survival analysis, patients assigned to the intervention condition had significantly fewer STDs compared with the control condition (hazard ratio [HR], 0.91; 95% confidence interval [CI], 0.84 to 0.99).

CONCLUSIONS

Showing a brief video in STD clinic waiting rooms reduced new infections nearly 10% overall in three clinics. This simple, low-intensity intervention may be appropriate for adoption by clinics that serve similar patient populations.

TRIAL REGISTRATION

http://www.ClinicalTrials.gov (#NCT00137670).

Alternatives to the randomized controlled trial

Public health researchers are addressing new research questions (e.g., effects of environmental tobacco smoke, Hurricane Katrina) for which the randomized controlled trial (RCT) may not be a feasible option. Drawing on the potential outcomes framework (Rubin Causal Model) and Campbellian perspectives, we consider alternative research designs that permit relatively strong causal inferences. In randomized encouragement designs, participants are randomly invited to participate in one of the treatment conditions, but are allowed to decide whether to receive treatment. In quantitative assignment designs, treatment is assigned on the basis of a quantitative measure (e.g., need, merit, risk). In observational studies, treatment assignment is unknown and presumed to be nonrandom. Major threats to the validity of each design and statistical strategies for mitigating those threats are presented.

Effect of a structural intervention for the prevention of intimate-partner violence and HIV in rural South Africa: a cluster randomised trial

BACKGROUND

HIV infection and intimate-partner violence share a common risk environment in much of southern Africa. The aim of the Intervention with Microfinance for AIDS and Gender Equity (IMAGE) study was to assess a structural intervention that combined a microfinance programme with a gender and HIV training curriculum.

METHODS

Villages in the rural Limpopo province of South Africa were pair-matched and randomly allocated to receive the intervention at study onset (intervention group, n=4) or 3 years later (comparison group, n=4). Loans were provided to poor women who enrolled in the intervention group. A participatory learning and action curriculum was integrated into loan meetings, which took place every 2 weeks. Both arms of the trial were divided into three groups: direct programme participants or matched controls (cohort one), randomly selected 14-35-year-old household co-residents (cohort two), and randomly selected community members (cohort three). Primary outcomes were experience of intimate-partner violence--either physical or sexual--in the past 12 months by a spouse or other sexual intimate (cohort one), unprotected sexual intercourse at last occurrence with a non-spousal partner in the past 12 months (cohorts two and three), and HIV incidence (cohort three). Analyses were done on a per-protocol basis. This trial is registered with ClinicalTrials.gov, number NCT00242957.

FINDINGS

In cohort one, experience of intimate-partner violence was reduced by 55% (adjusted risk ratio [aRR] 0.45, 95% CI 0.23-0.91; adjusted risk difference -7.3%, -16.2 to 1.5). The intervention did not affect the rate of unprotected sexual intercourse with a non-spousal partner in cohort two (aRR 1.02, 0.85-1.23), and there was no effect on the rate of unprotected sexual intercourse at last occurrence with a non-spousal partner (0.89, 0.66-1.19) or HIV incidence (1.06, 0.66-1.69) in cohort three.

INTERPRETATION

A combined microfinance and training intervention can lead to reductions in levels of intimate-partner violence in programme participants. Social and economic development interventions have the potential to alter risk environments for HIV and intimate-partner violence in southern Africa.

Sexual behaviour in context: a global perspective

Research aimed at investigating sexual behaviour and assessing interventions to improve sexual health has increased in recent decades. The resulting data, despite regional differences in quantity and quality, provide a historically unique opportunity to describe patterns of sexual behaviour and their implications for attempts to protect sexual health at the beginning of the 21st century. In this paper we present original analyses of sexual behaviour data from 59 countries for which they were available. The data show substantial diversity in sexual behaviour by region and sex. No universal trend towards earlier sexual intercourse has occurred, but the shift towards later marriage in most countries has led to an increase in premarital sex, the prevalence of which is generally higher in developed countries than in developing countries, and is higher in men than in women. Monogamy is the dominant pattern everywhere, but having had two or more sexual partners in the past year is more common in men than in women, and reported rates are higher in industrialised than in non-industrialised countries. Condom use has increased in prevalence almost everywhere, but rates remain low in many developing countries. The huge regional variation indicates mainly social and economic determinants of sexual behaviour, which have implications for intervention. Although individual behaviour change is central to improving sexual health, efforts are also needed to address the broader determinants of sexual behaviour, particularly those that relate to the social context. The evidence from behavioural interventions is that no general approach to sexual-health promotion will work everywhere and no single-component intervention will work anywhere. Comprehensive behavioural interventions are needed that take account of the social context in mounting individual-level programmes, attempt to modify social norms to support uptake and maintenance of behaviour change, and tackle the structural factors that contribute to risky sexual behaviour.